/*
 * Copyright (C) 2004 Baron Schwartz <baron at sequent dot org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, version 2.1.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
 * details.
 */

Date.parseFunctions = {count: 0};
Date.parseRegexes = [];
Date.formatFunctions = {count: 0};

Date.prototype.dateFormat = function (format) {
    if (Date.formatFunctions[format] == null) {
        Date.createNewFormat(format);
    }
    var func = Date.formatFunctions[format];
    return this[func]();
}

Date.createNewFormat = function (format) {
    var funcName = "format" + Date.formatFunctions.count++;
    Date.formatFunctions[format] = funcName;
    var code = "Date.prototype." + funcName + " = function(){return ";
    var special = false;
    var ch = '';
    for (var i = 0; i < format.length; ++i) {
        ch = format.charAt(i);
        if (!special && ch == "\\") {
            special = true;
        }
        else if (special) {
            special = false;
            code += "'" + String.escape(ch) + "' + ";
        }
        else {
            code += Date.getFormatCode(ch);
        }
    }
    eval(code.substring(0, code.length - 3) + ";}");
}

Date.getFormatCode = function (character) {
    switch (character) {
        case "d":
            return "String.leftPad(this.getDate(), 2, '0') + ";
        case "D":
            return "Date.dayNames[this.getDay()].substring(0, 3) + ";
        case "j":
            return "this.getDate() + ";
        case "l":
            return "Date.dayNames[this.getDay()] + ";
        case "S":
            return "this.getSuffix() + ";
        case "w":
            return "this.getDay() + ";
        case "z":
            return "this.getDayOfYear() + ";
        case "W":
            return "this.getWeekOfYear() + ";
        case "F":
            return "Date.monthNames[this.getMonth()] + ";
        case "m":
            return "String.leftPad(this.getMonth() + 1, 2, '0') + ";
        case "M":
            return "Date.monthNames[this.getMonth()].substring(0, 3) + ";
        case "n":
            return "(this.getMonth() + 1) + ";
        case "t":
            return "this.getDaysInMonth() + ";
        case "L":
            return "(this.isLeapYear() ? 1 : 0) + ";
        case "Y":
            return "this.getFullYear() + ";
        case "y":
            return "('' + this.getFullYear()).substring(2, 4) + ";
        case "a":
            return "(this.getHours() < 12 ? 'am' : 'pm') + ";
        case "A":
            return "(this.getHours() < 12 ? 'AM' : 'PM') + ";
        case "g":
            return "((this.getHours() %12) ? this.getHours() % 12 : 12) + ";
        case "G":
            return "this.getHours() + ";
        case "h":
            return "String.leftPad((this.getHours() %12) ? this.getHours() % 12 : 12, 2, '0') + ";
        case "H":
            return "String.leftPad(this.getHours(), 2, '0') + ";
        case "i":
            return "String.leftPad(this.getMinutes(), 2, '0') + ";
        case "s":
            return "String.leftPad(this.getSeconds(), 2, '0') + ";
        case "O":
            return "this.getGMTOffset() + ";
        case "T":
            return "this.getTimezone() + ";
        case "Z":
            return "(this.getTimezoneOffset() * -60) + ";
        default:
            return "'" + String.escape(character) + "' + ";
    }
}

Date.parseDate = function (input, format) {
    if (Date.parseFunctions[format] == null) {
        Date.createParser(format);
    }
    var func = Date.parseFunctions[format];
    return Date[func](input);
}

Date.createParser = function (format) {
    var funcName = "parse" + Date.parseFunctions.count++;
    var regexNum = Date.parseRegexes.length;
    var currentGroup = 1;
    Date.parseFunctions[format] = funcName;

    var code = "Date." + funcName + " = function(input){\n"
        + "var y = -1, m = -1, d = -1, h = -1, i = -1, s = -1;\n"
        + "var d = new Date();\n"
        + "y = d.getFullYear();\n"
        + "m = d.getMonth();\n"
        + "d = d.getDate();\n"
        + "var results = input.match(Date.parseRegexes[" + regexNum + "]);\n"
        + "if (results && results.length > 0) {"
    var regex = "";

    var special = false;
    var ch = '';
    for (var i = 0; i < format.length; ++i) {
        ch = format.charAt(i);
        if (!special && ch == "\\") {
            special = true;
        }
        else if (special) {
            special = false;
            regex += String.escape(ch);
        }
        else {
            obj = Date.formatCodeToRegex(ch, currentGroup);
            currentGroup += obj.g;
            regex += obj.s;
            if (obj.g && obj.c) {
                code += obj.c;
            }
        }
    }

    code += "if (y > 0 && m >= 0 && d > 0 && h >= 0 && i >= 0 && s >= 0)\n"
        + "{return new Date(y, m, d, h, i, s);}\n"
        + "else if (y > 0 && m >= 0 && d > 0 && h >= 0 && i >= 0)\n"
        + "{return new Date(y, m, d, h, i);}\n"
        + "else if (y > 0 && m >= 0 && d > 0 && h >= 0)\n"
        + "{return new Date(y, m, d, h);}\n"
        + "else if (y > 0 && m >= 0 && d > 0)\n"
        + "{return new Date(y, m, d);}\n"
        + "else if (y > 0 && m >= 0)\n"
        + "{return new Date(y, m);}\n"
        + "else if (y > 0)\n"
        + "{return new Date(y);}\n"
        + "}return null;}";

    Date.parseRegexes[regexNum] = new RegExp("^" + regex + "$");
    eval(code);
}

Date.formatCodeToRegex = function (character, currentGroup) {
    switch (character) {
        case "D":
            return {
                g: 0,
                c: null,
                s: "(?:Sun|Mon|Tue|Wed|Thu|Fri|Sat)"
            };
        case "j":
        case "d":
            return {
                g: 1,
                c: "d = parseInt(results[" + currentGroup + "], 10);\n",
                s: "(\\d{1,2})"
            };
        case "l":
            return {
                g: 0,
                c: null,
                s: "(?:" + Date.dayNames.join("|") + ")"
            };
        case "S":
            return {
                g: 0,
                c: null,
                s: "(?:st|nd|rd|th)"
            };
        case "w":
            return {
                g: 0,
                c: null,
                s: "\\d"
            };
        case "z":
            return {
                g: 0,
                c: null,
                s: "(?:\\d{1,3})"
            };
        case "W":
            return {
                g: 0,
                c: null,
                s: "(?:\\d{2})"
            };
        case "F":
            return {
                g: 1,
                c: "m = parseInt(Date.monthNumbers[results[" + currentGroup + "].substring(0, 3)], 10);\n",
                s: "(" + Date.monthNames.join("|") + ")"
            };
        case "M":
            return {
                g: 1,
                c: "m = parseInt(Date.monthNumbers[results[" + currentGroup + "]], 10);\n",
                s: "(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)"
            };
        case "n":
        case "m":
            return {
                g: 1,
                c: "m = parseInt(results[" + currentGroup + "], 10) - 1;\n",
                s: "(\\d{1,2})"
            };
        case "t":
            return {
                g: 0,
                c: null,
                s: "\\d{1,2}"
            };
        case "L":
            return {
                g: 0,
                c: null,
                s: "(?:1|0)"
            };
        case "Y":
            return {
                g: 1,
                c: "y = parseInt(results[" + currentGroup + "], 10);\n",
                s: "(\\d{4})"
            };
        case "y":
            return {
                g: 1,
                c: "var ty = parseInt(results[" + currentGroup + "], 10);\n"
                + "y = ty > Date.y2kYear ? 1900 + ty : 2000 + ty;\n",
                s: "(\\d{1,2})"
            };
        case "a":
            return {
                g: 1,
                c: "if (results[" + currentGroup + "] == 'am') {\n"
                + "if (h == 12) { h = 0; }\n"
                + "} else { if (h < 12) { h += 12; }}",
                s: "(am|pm)"
            };
        case "A":
            return {
                g: 1,
                c: "if (results[" + currentGroup + "] == 'AM') {\n"
                + "if (h == 12) { h = 0; }\n"
                + "} else { if (h < 12) { h += 12; }}",
                s: "(AM|PM)"
            };
        case "g":
        case "G":
        case "h":
        case "H":
            return {
                g: 1,
                c: "h = parseInt(results[" + currentGroup + "], 10);\n",
                s: "(\\d{1,2})"
            };
        case "i":
            return {
                g: 1,
                c: "i = parseInt(results[" + currentGroup + "], 10);\n",
                s: "(\\d{2})"
            };
        case "s":
            return {
                g: 1,
                c: "s = parseInt(results[" + currentGroup + "], 10);\n",
                s: "(\\d{2})"
            };
        case "O":
            return {
                g: 0,
                c: null,
                s: "[+-]\\d{4}"
            };
        case "T":
            return {
                g: 0,
                c: null,
                s: "[A-Z]{3}"
            };
        case "Z":
            return {
                g: 0,
                c: null,
                s: "[+-]\\d{1,5}"
            };
        default:
            return {
                g: 0,
                c: null,
                s: String.escape(character)
            };
    }
}

Date.prototype.getTimezone = function () {
    return this.toString().replace(
        /^.*? ([A-Z]{3}) [0-9]{4}.*$/, "$1").replace(
        /^.*?\(([A-Z])[a-z]+ ([A-Z])[a-z]+ ([A-Z])[a-z]+\)$/, "$1$2$3");
}

Date.prototype.getGMTOffset = function () {
    return (this.getTimezoneOffset() > 0 ? "-" : "+")
        + String.leftPad(Math.floor(this.getTimezoneOffset() / 60), 2, "0")
        + String.leftPad(this.getTimezoneOffset() % 60, 2, "0");
}

Date.prototype.getDayOfYear = function () {
    var num = 0;
    Date.daysInMonth[1] = this.isLeapYear() ? 29 : 28;
    for (var i = 0; i < this.getMonth(); ++i) {
        num += Date.daysInMonth[i];
    }
    return num + this.getDate() - 1;
}

Date.prototype.getWeekOfYear = function () {
    // Skip to Thursday of this week
    var now = this.getDayOfYear() + (4 - this.getDay());
    // Find the first Thursday of the year
    var jan1 = new Date(this.getFullYear(), 0, 1);
    var then = (7 - jan1.getDay() + 4);
    document.write(then);
    return String.leftPad(((now - then) / 7) + 1, 2, "0");
}

Date.prototype.isLeapYear = function () {
    var year = this.getFullYear();
    return ((year & 3) == 0 && (year % 100 || (year % 400 == 0 && year)));
}

Date.prototype.getFirstDayOfMonth = function () {
    var day = (this.getDay() - (this.getDate() - 1)) % 7;
    return (day < 0) ? (day + 7) : day;
}

Date.prototype.getLastDayOfMonth = function () {
    var day = (this.getDay() + (Date.daysInMonth[this.getMonth()] - this.getDate())) % 7;
    return (day < 0) ? (day + 7) : day;
}

Date.prototype.getDaysInMonth = function () {
    Date.daysInMonth[1] = this.isLeapYear() ? 29 : 28;
    return Date.daysInMonth[this.getMonth()];
}

Date.prototype.getSuffix = function () {
    switch (this.getDate()) {
        case 1:
        case 21:
        case 31:
            return "st";
        case 2:
        case 22:
            return "nd";
        case 3:
        case 23:
            return "rd";
        default:
            return "th";
    }
}

String.escape = function (string) {
    return string.replace(/('|\\)/g, "\\$1");
}

String.leftPad = function (val, size, ch) {
    var result = new String(val);
    if (ch == null) {
        ch = " ";
    }
    while (result.length < size) {
        result = ch + result;
    }
    return result;
}

Date.daysInMonth = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31];
Date.monthNames =
    ["January",
        "February",
        "March",
        "April",
        "May",
        "June",
        "July",
        "August",
        "September",
        "October",
        "November",
        "December"];
Date.dayNames =
    ["Sunday",
        "Monday",
        "Tuesday",
        "Wednesday",
        "Thursday",
        "Friday",
        "Saturday"];
Date.y2kYear = 50;
Date.monthNumbers = {
    Jan: 0,
    Feb: 1,
    Mar: 2,
    Apr: 3,
    May: 4,
    Jun: 5,
    Jul: 6,
    Aug: 7,
    Sep: 8,
    Oct: 9,
    Nov: 10,
    Dec: 11
};
Date.patterns = {
    ISO8601LongPattern: "Y-m-d H:i:s",
    ISO8601ShortPattern: "Y-m-d",
    ShortDatePattern: "n/j/Y",
    LongDatePattern: "l, F d, Y",
    FullDateTimePattern: "l, F d, Y g:i:s A",
    MonthDayPattern: "F d",
    ShortTimePattern: "g:i A",
    LongTimePattern: "g:i:s A",
    SortableDateTimePattern: "Y-m-d\\TH:i:s",
    UniversalSortableDateTimePattern: "Y-m-d H:i:sO",
    YearMonthPattern: "F, Y"
};
